Designer Wardrobe was founded in 2015 and brings the buyer and sellers of used clothes, shoes and accessories from high-end designers together.
The site has 325,000 users.
Starting out 10 years ago as a Facebook marketplace page, the business now has one in 10 New Zealand women signed up, chief executive Aidan Bartlett told RNZ's Nights programme.
There was lots of competition out there, but a strict focus had allowed the business to carve a strong niche, he said.
"Our point of difference has been being hyper-specialised to the fashion experience and discovering fashion and trust has always been a key focus for us too.
"Whenever you buy something on Designer Wardrobe, you're not actually paying the seller directly, you're paying Designer Wardrobe, and then we hold the funds that you've paid until that item has been delivered to you, and then we pay the seller."
The model had paid off, he said.
"It is a really great proposition for both the buyer and the seller. A buyer on Designer Wardrobe will typically buy something for around 60 percent off what it cost originally.
"From the seller perspective, it just means that you don't throw that item away. You essentially turn it into cash."
A typical item took two days to sell, he said.
The move into Australia was a natural progression, he said.
"We did it mainly because, we have seen this, big appetite from both buyers and sellers in Australia.
"Typically, buyers in Australia are trying to purchase items from New Zealanders from brands that are much more prevalent in New Zealand than they are in Australia, which made us realise that there's a lot of cross pollination between brands in both Australia and New Zealand."
The company had lofty goals for the next few years, he said.
"The mission for Designer Wardrobe is to have pre-loved [clothes] in every closet in Australasia."
